CN111448747B - Power module - Google Patents

Power module Download PDF

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Publication number
CN111448747B
CN111448747B CN201780097627.5A CN201780097627A CN111448747B CN 111448747 B CN111448747 B CN 111448747B CN 201780097627 A CN201780097627 A CN 201780097627A CN 111448747 B CN111448747 B CN 111448747B
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China
Prior art keywords
switching element
threshold voltage
electrode
power module
initial
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CN201780097627.5A
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CN111448747A (en
Inventor
铃木健一
宫泽亘
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Shindengen Electric Manufacturing Co Ltd
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Shindengen Electric Manufacturing Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/26—Testing of individual semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/14—Modifications for compensating variations of physical values, e.g. of temperature
    • H03K17/145—Modifications for compensating variations of physical values, e.g. of temperature in field-effect transistor switches
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/16—Modifications for eliminating interference voltages or currents
    • H03K17/161—Modifications for eliminating interference voltages or currents in field-effect transistor switches
    • H03K17/162—Modifications for eliminating interference voltages or currents in field-effect transistor switches without feedback from the output circuit to the control circuit
    • H03K17/163—Soft switching
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/18—Modifications for indicating state of switch
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
    • G01R19/16552—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies in I.C. power supplies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/40—Testing power supplies

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Inverter Devices (AREA)
  • Power Conversion In General (AREA)

Abstract

The power module 1 of the present invention is configured to be switched between a control mode for controlling on/off operations of a switching element 200 having a first electrode, a second electrode, and a third electrode, and a degradation determination mode for calculating Δvgs from information including a threshold voltage detected before a stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and determining whether or not the device is degraded from information including Δvgs. According to the power module 1 of the present invention, it is possible to determine whether or not the power module is deteriorated during operation, and therefore, it is possible to prevent breakage of the device, and it is also possible to improve the working efficiency and reduce the cost.

Description

Power module
Technical Field
The present invention relates to a power module.
Background
Conventionally, a power module that controls on/off operation of a switching element has been widely known (for example, refer to patent document 1).
As shown in fig. 16, a conventional power module 900 includes: a switching element 800 having a first electrode, a second electrode, and a gate electrode; and a gate voltage control part 910 which controls a gate voltage to control on/off operation of the switching element 800.
According to the conventional power module 900, the on/off operation of the switching element 800 can be controlled by controlling the gate voltage by the gate voltage control unit 910.
[ Prior Art literature ]
[ patent document 1 ] International publication No. 2012/153459
However, in recent years, there has been a demand for a power module capable of determining whether or not a device is degraded (hereinafter, simply referred to as "degraded") at the time of actual use of the device. However, in reality, it is very difficult to determine whether or not to deteriorate in actual use (at the time of operation), and there is a possibility that the device may be broken when it is continued to be used in a deteriorated state. In order to avoid the above-described problem, it is conceivable to replace the device periodically before degradation, but in this case, not only the replacement frequency becomes high and the working efficiency is lowered, but also the cost increases.
Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a power module capable of preventing breakage of a device by determining whether to deteriorate at the time of actual use, and which is also capable of improving work efficiency and reducing cost.
Disclosure of Invention
【1】 The power module of the present invention is configured to be switched between a control mode for controlling on/off operations of a switching element having a first electrode, a second electrode, and a third electrode, and a degradation determination mode for calculating Δvgs from information including a threshold voltage detected before a stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and determining whether or not a device is degraded from information including the Δvgs.
In addition, in the present specification, Δvgs means: the threshold voltage is measured before the stress current is supplied to the switching element, and after the stress current is supplied to the switching element for a predetermined period, a value calculated from the two threshold voltages obtained by measuring the threshold voltage again (basically, a difference between the threshold voltage detected before the stress current is supplied to the switching element and the threshold voltage detected after the stress current is supplied to the switching element).
【2】 In the power module of the present invention, it is preferable that: the switching element; a third electrode voltage control section that controls a third electrode voltage so as to stepwise increase the third electrode voltage when a threshold voltage is measured in the degradation determination mode, and that controls the third electrode voltage so as to control on/off operation of the switching element in the control mode; an on/off state determination unit that determines an on/off state of the switching element in the degradation determination mode; a storage unit that stores an initial Δvgs of the switching element, and stores the third electrode voltage applied to the third electrode as a threshold voltage after the on/off state determination unit determines that the switching element is in an on state in the degradation determination mode; a degradation determination unit that calculates the Δvgs from information including a threshold voltage detected before the stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and determines whether the device is degraded or not from information including the Δvgs and the initial Δvgs in the degradation determination mode; and a power circuit connected in series with the switching element and having a load resistor and a driving power supply.
【3】 In the power module of the present invention, it is preferable that: the power module is configured to perform an initial measurement mode in which the initial Δvgs of the switching element is detected before the control mode is performed, and in the initial measurement mode, the third electrode voltage control unit controls the third electrode voltage so that the third electrode voltage is gradually increased when a threshold voltage is measured, the on/off state determination unit determines an on/off state of the switching element, and the storage unit stores the third electrode voltage applied to the third electrode as a threshold voltage after the on/off state determination unit determines that the switching element is in an on state, and the deterioration determination unit calculates the initial Δvgs based on information including an initial threshold voltage that is the threshold voltage detected before the stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element.
【4】 In the power module of the present invention, it is preferable that: in the control mode, the third electrode voltage control unit controls the third electrode voltage based on information including the initial threshold voltage measured in the initial measurement mode when the switching element is turned on.
【5】 In the power module of the present invention, it is preferable that: the device further includes a temperature detection unit configured to detect an operation temperature of the switching element, wherein the storage unit further stores information on a temperature characteristic of a threshold voltage in the switching element and information including an initial operation temperature, and the degradation determination unit determines whether the device is degraded based on information on the temperature characteristic of the threshold voltage in the switching element and information including the initial Δvgs, the Δvgs detected in the degradation determination mode, the initial operation temperature, and the operation temperature of the switching element detected by the temperature detection unit in the degradation determination mode.
【6】 In the power module of the present invention, it is preferable that: the control device further includes a threshold voltage calculating unit that calculates a threshold voltage at the time of operation of the switching element based on information including the operation temperature of the switching element, the initial threshold voltage, and the initial operation temperature of the switching element detected by the temperature detecting unit, and based on information related to a temperature characteristic of the threshold voltage in the switching element, and in the control mode, the third electrode voltage control unit controls the third electrode voltage based on the threshold voltage at the time of operation calculated by the threshold voltage calculating unit when the switching element is placed in an on state.
【7】 In the power module of the present invention, it is preferable that: the power module further includes a temperature characteristic calculation unit that calculates a temperature characteristic of a threshold voltage of the switching element, wherein the third electrode voltage control unit controls the third electrode voltage so as to gradually increase the third electrode voltage in the temperature characteristic measurement mode, the on/off state determination unit determines whether the switching element is on, and the storage unit stores the third electrode voltage applied to the third electrode as the threshold voltage at the time of temperature characteristic measurement of the switching element, after the on/off state determination unit determines that the switching element is in the on state, and the temperature characteristic calculation unit calculates threshold voltage information based on the temperature characteristic of the switching element including the initial threshold voltage, the initial operating temperature of the switching element after the initial threshold voltage is measured, the temperature characteristic of the switching element detected by the temperature detection unit in the temperature characteristic measurement mode, and the temperature characteristic of the switching element.
【8】 In the power module of the present invention, it is preferable that: the degradation determination mode is one in which the on/off state determination unit determines the on/off state of the switching element based on a result of detection of the first electrode current detected by the first electrode current detection unit.
【9】 In the power module of the present invention, it is preferable that: the device further includes an alarm unit that externally displays a result of detection of whether or not the device is degraded, which is determined by the degradation determination unit.
【10】 In the power module of the present invention, it is preferable that: further, the switching device further includes a stress current supply unit that supplies the stress current to the switching element in the degradation determination mode.
【11】 In the power module of the present invention, it is preferable that: the power supplied in the power circuit is constant, and in the degradation determination mode, the stress current is supplied from the current flowing in the driving power supply.
【12】 In the power module of the present invention, it is preferable that: in the case of detecting the threshold voltage of the switching element, the third electrode voltage control section controls the third electrode voltage so that the third electrode voltage increases stepwise with the passage of time.
【13】 In the power module of the present invention, it is preferable that: when detecting the threshold voltage of the switching element, the third electrode voltage control unit controls the third electrode voltage so that the third electrode voltage becomes a pulse-shaped voltage having a pulse with a large amplitude with the passage of time.
【14】 In the power module of the present invention, it is preferable that: the switching element is made of GaN, siC or Ga 2 O 3 Is formed of the material of (a).
Effects of the invention
According to the power module of the present invention, since the power module is configured to implement the degradation determination mode in which Δvgs is calculated from information including the threshold voltage detected before the stress current is supplied to the switching element and the threshold voltage detected after the stress current is supplied to the switching element, and whether or not the device is degraded is determined from the information including the Δvgs, it is possible to determine whether or not the device is degraded in actual use (at the time of operation), and to prevent breakage of the device due to continued use in a degraded state.
According to the power module of the present invention, since the power module is configured to implement the degradation determination mode in which Δvgs is calculated from information including the threshold voltage detected before the stress current is supplied to the switching element and the threshold voltage detected after the stress current is supplied to the switching element, and whether or not the device is degraded is determined from the information including the Δvgs, a user using the device can know the time of degradation of the device, and since the device can be replaced at this time (the time of degradation stage), it is unnecessary to replace the device periodically before the device is degraded. Therefore, since the replacement frequency becomes low, the work efficiency can be improved and the cost can be reduced.
Drawings
Fig. 1 is a circuit diagram of a power module 1 according to a first embodiment.
Fig. 2 is a schematic diagram showing a relationship between threshold voltage Vth and operating temperature T of the switching element.
Fig. 3 shows that the threshold voltage (initial threshold voltage Vth) Is measured before the stress current Is supplied to the switching element in the initial measurement mode 0 ) Block diagram at the time.
Fig. 4 is a schematic diagram of a gate voltage shown for explaining an initial threshold voltage measurement mode and/or a degradation determination mode in the first embodiment.
Fig. 5 is a schematic waveform diagram of the gate voltage in the degradation determination mode.
Fig. 6 Is a block diagram of the initial measurement mode when the threshold voltage Is measured after the stress current Is supplied to the switching element.
Fig. 7 is a block diagram of a control mode.
Fig. 8 is a schematic diagram showing a time variation of the gate voltage (gate-source voltage) Vgs shown for explaining an effect when a gate voltage slightly exceeding a threshold voltage is applied to the gate electrode in the control mode. Fig. 8 (a) is a schematic diagram showing a time change of the gate-source voltage Vgs when a gate voltage is applied to the gate electrode in the power module according to the comparative example, and fig. 8 (b) is a schematic diagram showing a time change of the gate-source voltage Vgs when a gate voltage slightly exceeding the threshold voltage is applied to the gate electrode in the power module 1 according to the first embodiment.
Fig. 9 Is a block diagram of a case where the threshold voltage Is measured before the stress current Is supplied to the switching element in the degradation determination mode.
Fig. 10 Is a block diagram of a case where the threshold voltage Is measured after the stress current Is supplied to the switching element in the degradation determination mode.
Fig. 11 is a block diagram showing a temperature characteristic measurement mode in the second embodiment.
Fig. 12 is a circuit diagram of a power module 2 according to the third embodiment.
Fig. 13 is a circuit diagram of a power module 3 according to a first modification.
Fig. 14 is a circuit diagram of a power module 4 according to a second modification.
Fig. 15 is a schematic diagram showing an initial threshold voltage measurement mode and/or a degradation determination measurement mode of the power module according to the third modification.
Fig. 16 is a diagram for explaining a conventional power module 900.
Detailed Description
Hereinafter, the power module of the present invention will be described according to the embodiments shown in the drawings. The drawings are schematic and do not strictly reflect actual circuit configurations and diagrams.
Embodiment one
1. The power module 1 according to the first embodiment is constituted
As shown in fig. 1, a power module 1 according to a first embodiment includes: a switching element 200; a gate voltage control section 10 (third electrode voltage control section); a switching current detecting section (first electrode current detecting section) 20; an on/off state determination unit 30; a storage unit 40; a temperature detecting section 50; a degradation determination unit 60; a threshold voltage calculation unit 70; an alarm unit 80; a measurement current supply unit 100; a stress current supply unit 102; and a power circuit 400. The power module 1 according to the first embodiment is covered with a package formed of a resin, ceramic, or the like having high heat resistance and high insulation. In the power module 1 according to the first embodiment, there is provided: input of DC power supply voltage V DD (+) side input terminal T1 of (a); a (-) side input terminal T2 on the ground side; a (+) -side output terminal T3; a (-) side output terminal T4 on the ground side; a control terminal T5 to which a drive signal (e.g., gate pulse) Pg is input; and an alarm signal terminal T6 for transmitting an alarm signal to an external alarm unit (not shown). A switch SW3 is provided between the power circuit 400 and the switching element 200.
A power supply voltage V is applied between the (+) side input terminal T1 and the (-) side input terminal T2 DD A gate driving power supply 300. The gate driving power supply 300 is connected to the gate electrode of the switching element 200 via the gate voltage control unit 10, and supplies a voltage to the gate electrode. At the position ofThe power circuit 400 is connected to the (+) side output terminal T3 and the (-) side output terminal T4.
The power circuit 400 is connected in series with the switching element 200. The power circuit 400 includes a load resistor 410 and a dc driving power supply 420, and the load resistor 410 and the dc driving power supply 420 are connected in series between a (+) side output terminal T3 and a (-) side output terminal T4. Further, the (-) side output terminal T4 is grounded.
The switching element 200 includes a source electrode (second electrode); a drain electrode (first electrode) and a gate electrode (third electrode). If a gate voltage (third electrode voltage) exceeding a threshold voltage is applied to the gate electrode, the switching element 200 becomes on-state, and if the gate voltage is lower than the threshold voltage, the switching element 200 becomes off-state. The gate voltage is supplied from the power supply voltage VDD and is controlled by the gate voltage control section 10. In addition, although a MOSFET is used as the switching element 200 in the first embodiment, other suitable switching elements may be used. The switching element 200 is formed by a material containing GaN. When GaN is included in the switching element 200, the difference between the absolute maximum rated voltage of the gate electrode and the threshold voltage becomes small.
The drain electrode of the switching element 200 is connected to the power circuit 400 via a (+) side output terminal T3. The gate electrode of the switching element 200 is connected to the gate voltage control unit 10. The source electrode of the switching element 200 is connected to the (-) side output terminal T4 via a resistor.
When the threshold voltage is measured in the initial measurement mode and the degradation determination mode based on the input drive signal Pg (e.g., gate pulse), the gate voltage control section 10 controls the gate voltage so that the gate voltage is stepwise raised, and in the control mode, the gate voltage control section 10 controls the gate voltage so as to control the on/off operation of the switching element 200. The gate voltage control unit 10 is connected to the on/off state determination unit 30, the storage unit 40, and the threshold voltage calculation unit 70.
The switching current detecting unit 20 is connected to the source electrode of the switching element 200, and in the initial measurement mode and the degradation determination mode, the switching current detecting unit 20 detects the switching current Id (first electrode current, drain current, or source current) of the switching element 200. The switching current detecting unit 20 is connected to the on/off state determining unit 30. The switching current detecting unit 20 is configured to measure a current flowing through a resistor connected to the source electrode of the switching element 200 and convert the current into a voltage, but a suitable detecting device (e.g., rogowski coil) may be used.
In the initial measurement mode and the degradation determination mode, the on/off state determination unit 30 determines the on/off state of the switching element 200 based on the detection result of the switching current received from the switching current detection unit 20. The on/off state determination unit 30 is connected to the gate voltage control unit 10 and the switching current detection unit 20.
In the storage unit 40, information on the temperature characteristics of the threshold voltage in the switching element 200 and a standard value for degradation determination are stored in advance. The storage unit 40 stores the initial Δvgs and the initial threshold voltage Vth of the switching element 200 detected and calculated in the initial measurement mode or the degradation determination mode 0 And threshold voltage Vth, and initial operation temperature T of memory switching element 200 0 An operating temperature T. In the initial measurement mode and the degradation determination mode, after the on/off state determination unit 30 determines that the switching element 200 is in the on state, the storage unit 40 stores the gate voltage applied to the gate electrode as a threshold voltage. The storage unit 40 is connected to the gate voltage control unit 10, the temperature detection unit 50, the degradation determination unit 60 (specifically, the Δvgs calculation unit 62 and the standard determination unit 64), and the threshold voltage calculation unit 70.
In addition, the initial operating temperature T 0 Refers to measurement of initial threshold voltage Vth 0 The temperature of the latter.
The temperature detecting unit 50 has a temperature detecting element 52. As the temperature detecting element 52, a suitable temperature detecting element such as a diode or a thermistor can be used.
In the degradation determination mode, the degradation determination unit 60 calculates Δvgs from information including a threshold voltage detected before the stress current supply unit 102 supplies the stress current Is to the switching element 200 and a threshold voltage detected after the stress current supply unit 102 supplies the stress current Is to the switching element 200, and determines whether or not to degrade based on information including the Δvgs and the initial Δvgs stored in the storage unit 40. The degradation determination unit 60 includes a Δvgs calculation unit 62 and a standard determination unit 64.
The Δvgs calculating unit 62 is connected to the storage unit 40 and the temperature detecting unit 50, and the Δvgs calculating unit 62 calculates Δvgs (or initial Δvgs) in the degradation determination mode and the initial measurement mode. In the degradation determination mode, the Δvgs calculation unit 62 calculates the threshold voltage of the memory unit 40 based on the information of the operating temperature from the temperature detection unit 50 (i.e., based on the information of the threshold voltage stored in the memory unit 40 in consideration of the initial operating temperature T 0 The threshold voltage after the temperature change) to calculate avgs.
The criterion determination unit 64 compares the "difference between the Δvgs calculated by the Δvgs calculation unit 62 and the initial Δvgs stored in the storage unit 40" with the criterion value stored in the storage unit 40. When the difference between Δvgs and the initial Δvgs is larger than the standard value, it is determined to be in degradation.
The threshold voltage calculation unit 70 reads the initial threshold voltage Vth including the switching element 200 from the storage unit 40 0 Initial operating temperature T of switching element 200 0 And information related to the temperature characteristics of the threshold voltage in the switching element 200, and the operating temperature T of the switching element 200 is read from the temperature detecting unit 50 and substituted into vth=vth 0 －α(T－T 0 ) The threshold voltage Vth during operation is calculated based on the characteristics of (a).
The alarm unit 80 externally displays the detection result of whether or not the degradation is determined by the degradation determination unit 60. In particular, when the criterion determination unit 64 determines that the vehicle is degraded, the alarm unit 80 transmits an alarm signal to an external alarm.
The measurement current supply unit 100 is connected to the drain electrode of the switching element 200 via the switch SW1, and supplies the measurement current Im having a small current to the drain electrode of the switching element 200 by turning on the switch SW1 in the degradation determination mode and the initial measurement mode.
The stress current supply unit 102 is connected in parallel with the measurement current supply unit 100. The stress current supply unit 102 Is connected to the drain electrode of the switching element 200 via the switch SW2, and supplies the stress current Is having a large current to the switching element 200 by turning on the switch SW2 in the degradation determination mode and the initial measurement mode.
Further, the information on the temperature characteristic of the threshold voltage in the switching element 200 is: the temperature coefficient of the threshold voltage in the switching element 200 is set to α, the threshold voltage during operation is set to Vth, and the initial threshold voltage is set to Vth 0 The initial threshold voltage Vth is measured with the operating temperature of the switching element 200 detected by the temperature detecting unit 50 being T 0 The initial operating temperature of the switching element 200 is then taken as T 0 After that, vth=vth is satisfied 0 －α(T－T 0 ) Is described in relation to the relation (see fig. 2). That is, the relationship between the threshold voltage Vth and the operating temperature T of the switching element 200 is a linear function having a negative slope.
2. Operation of the power module 1 according to embodiment one
The power module 1 according to the first embodiment Is configured to switch between an initial measurement mode in which an initial Δvgs of the switching element 200 Is detected before the control mode Is implemented, a control mode in which on/off operation of the switching element 200 having a drain electrode, a source electrode, and a gate electrode Is controlled, and a degradation determination mode in which Δvgs Is calculated from information including a threshold voltage detected before the stress current Is supplied to the switching element 200 and a threshold voltage detected after the stress current Is supplied to the switching element 200, and whether the device Is degraded Is determined from information including Δvgs. The power module 1 according to the first embodiment first detects and calculates the initial threshold voltage Vth by implementing the initial measurement mode 0 Initial Δvgs and initial operating temperature T 0 . Subsequently, the on/off operation of the switching element 200 is controlled by implementing the control mode. Then, at a predetermined time (for example, after the control mode is performed for a predetermined time), the control mode is switched to the degradation determination mode to performDegradation determination is performed. If there is no problem in the result of the degradation determination, the control mode is returned again, and if there is a problem, an alarm signal is transmitted from the alarm unit 80 to an external alarm.
(1) Initial measurement mode
The initial measurement mode is to measure the initial operation temperature T of the switching element 200 0 Initial threshold voltage Vth 0 And an initial Δvgs pattern. This mode is performed before the control mode is implemented (before the switch SW3 is turned on and power is supplied from the driving power source 420 to the switching element 200).
Further, the memory unit 40 is previously caused to store information related to the temperature characteristics of the threshold voltage in the switching element 200. The threshold voltage Vth is from the initial threshold voltage due to temperature variation of the switching element 200 0 Since the threshold voltage becomes smaller if the temperature becomes higher (see fig. 2), it is difficult to accurately calculate Δvgs without calculating the threshold voltage after considering the temperature fluctuation. In addition, since Δvgs is actually a small value, Δvgs must also be calculated using a threshold voltage that takes into account temperature fluctuations.
(1-1) first measurement of threshold Voltage
The switch SW1 is turned on with the switches SW2 and SW3 turned off, and the measurement current Im is supplied from the measurement current supply unit 100 to the switching element 200 (see fig. 1 and 3). Subsequently, the gate voltage control section 10 controls the gate voltage so as to apply a voltage lower than the envisaged initial threshold voltage to the gate electrode. At this time, since the switching current (the value of the switching current is 0) cannot be detected by the switching current detecting section 20, the on/off state determining section 30 determines that the switching element 200 is in the off state. If the on/off state determination unit 30 determines that the switching element 200 is in the off state, the gate voltage control unit 10 controls the gate voltage so as to raise the gate voltage by one stage (see fig. 4).
The gate voltage is stepped up (specifically, stepped up) after repeating the above-described process, and when the switching current is detected by the switching current detecting section 20 (switching currentWhen the value of (a) is not 0), the on/off state determination unit 30 determines that the switching element 200 is in the on state (see fig. 3). At this time, the operating temperature of the switching element 200 detected by the temperature detecting unit 50 is set as the initial operating temperature T 0 To the memory unit 40, and the gate voltage control unit 10 sets the gate voltage Vgs applied to the gate electrode as the initial threshold voltage Vth 0 To be sent to the storage unit 40. In the memory unit 40, the gate voltage Vgs is set as the initial threshold voltage Vth 0 To be stored.
(1-2) providing a stress current Is
Next, the switch SW2 Is turned on with the switches SW1 and SW3 turned off, and the stress current Is supplied from the stress current supply unit 102 to the switching element 200 with a predetermined current amount (see fig. 1 and 5). The gate voltage control unit 10 controls the gate voltage so that the switching element 200 is turned on for a predetermined period of time (see fig. 5). Since a predetermined electric power is applied to the switching element 200, the switching element 200 generates heat.
(1-3) determination of threshold Voltage for the second time
Subsequently, the switch SW1 is turned on in a state where the switches SW2 and SW3 are turned off, and the measurement current Im is supplied from the measurement current supply unit 100 to the switching element 200 (see fig. 1).
The threshold voltage Is measured in the same manner as in (1-1) above, and the gate voltage control unit 10 uses the gate voltage Vgs applied to the gate electrode as "threshold voltage detected after the stress current Is supplied to the switching element" (threshold voltage Vth) 1 ) To be sent to the storage unit 40 (see fig. 6). In the memory section 40, the gate voltage Vgs is set as the threshold voltage Vth 1 To be stored.
(1-4) calculation of ΔVgs
Next, in the Δvgs calculation unit 62 of the degradation determination unit 60, the initial threshold voltage Vth is calculated from 0 And threshold voltage Vth 1 (from the initial threshold voltage Vth 0 Subtracting the threshold voltage Vth 1 ) To calculate Δvgs (initial Δvgs). The Δvgs calculating unit 62 transmits the calculated Δvgs (initial Δvgs) to the memoryThe storage unit 40 stores the Δvgs as an initial Δvgs (see fig. 6).
(2) Control mode
When the initial measurement mode is completed, the switch SW3 is turned on with the switches SW1 and SW2 turned off, and the power circuit 400 and the switching element 200 are turned on, so that a current is supplied from the driving power supply 420 to the switching element 200 (see fig. 1).
When the switching element 200 is turned on, the gate voltage applied to the gate electrode is determined as follows (see fig. 7).
First, the temperature detecting unit 50 detects the operation temperature T of the switching element 200 via the temperature detecting element 52.
The threshold voltage calculation unit 70 reads the initial threshold voltage Vth including the switching element 200 detected in the initial measurement mode from the storage unit 40 0 Measurement of initial threshold Voltage Vth 0 Initial operating temperature T of the switching element 200 0 And information α related to the temperature characteristic of the threshold voltage in the switching element 200, and the operating temperature T of the switching element 200 is read from the temperature detecting unit 50 and substituted into vth=vth 0 －α(T－T 0 ) The threshold voltage Vth during operation is calculated based on the characteristics of (a).
Subsequently, the gate voltage control unit 10 applies a gate voltage slightly exceeding the threshold voltage Vth calculated by the threshold voltage calculation unit 70 to the gate electrode (see fig. 8 b) based on the threshold voltage Vth at the time of operation. Accordingly, the on/off operation of the switching element 200 is controlled.
In the power module 1 according to the first embodiment, the gate voltage may be controlled in sequence following the temperature of the switching element 200, or the operating temperature of the switching element 200 may be detected at predetermined intervals to calculate the threshold voltage at the time of operation, and the gate voltage may be controlled based on the threshold voltage at the time of operation.
(3) Degradation determination mode
Power module 1 according to embodiment 1At a predetermined timing (for example, each time the control mode is executed for a predetermined time), the degradation determination mode is executed. Deterioration determination unit 60 determines the initial operation temperature T based on information about the temperature characteristics of the threshold voltage in switching element 200, and based on the information including initial Δvgs, Δvgs detected in the deterioration determination mode, and the temperature characteristics of the threshold voltage 0 And information of the operating temperature T of the switching element 200 detected by the temperature detecting section 50 in the degradation determination mode to determine whether or not to degrade.
In the degradation determination mode, the following applies: (3-1) first measurement of threshold voltage, (3-2) supply of stress current, (3-3) second measurement of threshold voltage, (3-4) calculation of Δvgs, and (3-5) standard determination (degradation determination). The method for measuring the threshold voltage from (3-1) to (3-3) is the same as the method for measuring the threshold voltage from (1-1) to (1-3) in the initial measurement mode. That is, in the degradation determination mode, the threshold voltage is measured for the first time (3-1) to determine the operating temperature T of the switching element 200 at this time 1 Detected threshold voltage Vth 2 Stored in the memory section 40 (see fig. 9), the stress current Is supplied under the same condition as the stress current supplied in the initial measurement mode (3-2), and then the threshold voltage Vth Is detected by measuring the threshold voltage (3-3) for the second time 3 And the detected threshold voltage Vth 3 Stored in the storage unit 40 (see fig. 10).
(3-4) calculation of ΔVgs
The Δvgs calculating portion 62 calculates the initial operating temperature T based on the initial operating temperature T transmitted from the storage portion 40 0 The operation temperature T of the switching element 200 stored in the storage unit 40 by measuring the threshold voltage in the degradation determination mode for the first time 1 Threshold voltage Vth 2 The threshold voltage Vth stored in the memory unit 40 by measuring the threshold voltage a second time 3 To calculate Δvgs (see fig. 10).
Specifically, first, the degradation determination unit 60 (Δvgs calculation unit 62) reads the initial threshold voltage Vth including the switching element 200 (detected in the initial measurement mode) from the storage unit 40 0 Measurement of initial threshold Voltage Vth 0 Initial operating temperature T of the switching element 200 0 The operation temperature T of the switching element 200 stored in the storage unit 40 when the threshold voltage in the degradation determination mode is measured for the first time 1 Threshold voltage Vth 2 A threshold voltage Vth stored in the memory unit 40 when the threshold voltage is measured for the second time 3 Is read out and substituted into vth=vth by information (including temperature coefficient α) related to the temperature characteristic of the threshold voltage in the switching element 200 0 －α(T－T 0 ) To calculate the threshold voltage Vth after temperature correction 2 ' and Vth 3 ’。
Then, from the threshold voltage Vth after temperature correction 2 ' subtracting Vth 3 ' to calculate Δvgs. The calculated Δvgs is sent to the criterion determination unit 64.
(3-5) Standard determination (deterioration determination)
Then, the criterion determination unit 64 reads the initial Δvgs and the criterion value from the storage unit 40, and calculates (Δvgs—initial Δvgs) from the Δvgs sent from the Δvgs calculation unit 62, and compares the value with the criterion value. The alarm unit 80 externally displays the detection result of whether or not the degradation is determined by the degradation determination unit 60 (the criterion determination unit 64). When (Δvgs—initial Δvgs) is smaller than the standard value, it is determined that there is no degradation, and the power module 1 according to the first embodiment returns to the control mode. When (Δvgs—initial Δvgs) is larger than the standard value, an alarm signal is sent from the alarm unit 80 to an external alarm (not shown).
3. Effects of the power module 1 according to the first embodiment
According to the power module 1 of the first embodiment, since it Is configured to implement the degradation determination mode in which Δvgs Is calculated from information including the threshold voltage detected before the stress current Is supplied to the switching element 200 and the threshold voltage detected after the stress current Is supplied to the switching element 200, and whether or not the device Is degraded Is determined from the information including Δvgs, it Is possible to determine whether or not the device Is degraded in actual use (during operation), and it Is possible to prevent breakage of the device due to continued use in a degraded state.
Further, according to the power module 1 of the first embodiment, since it Is configured to implement the degradation determination mode in which Δvgs Is calculated from information including the threshold voltage detected before the stress current Is supplied to the switching element 200 and the threshold voltage detected after the stress current Is supplied to the switching element 200, and whether or not the device Is degraded Is determined from the information including the Δvgs, a user using the device can know the time of degradation of the device, and since the device can be replaced at that time (the time of degradation stage), it Is unnecessary to replace the device periodically before the device Is degraded. Therefore, since the replacement frequency becomes low, the work efficiency can be improved and the cost can be reduced.
The power module 1 according to the first embodiment includes the degradation determination unit 60, and the degradation determination unit 60 Is configured to determine, in the degradation determination mode, a threshold voltage Vth detected before the stress current Is supplied to the switching element 200 based on the threshold voltage Vth 2 And a threshold voltage Vth detected after the stress current Is supplied to the switching element 200 3 To calculate Δvgs, and to determine whether the device is degraded or not based on information including the Δvgs and the initial Δvgs. With this configuration, even if there is a variation in the threshold voltage of the switching element 200 due to a manufacturing variation, the actual threshold voltage of the switching element 200 actually provided in the power module can be measured, and Δvgs can be accurately calculated. In this way, it is possible to accurately determine whether or not the degradation is occurring in actual use.
According to the power module 1 of the first embodiment, in the initial measurement mode, the deterioration determination unit 60 determines the deterioration of the switching element 200 based on the initial threshold voltage Vth including the threshold voltage detected before the stress current Is supplied to the switching element 0 A threshold voltage Vth detected after the stress current Is supplied to the switching element 200 1 Since the initial Δvgs is calculated from the information of (a), even when the actual threshold voltage fluctuates from the designed threshold voltage due to the manufacturing variation of the switching element, the actual threshold voltage can be calculated from the actual threshold voltageThe value voltage (not the design value, but a real one corresponding to the switching element thereof even if a deviation occurs) calculates Δvgs. Therefore, the actual degradation can be accurately determined, not the design value.
In addition, according to the power module 1 according to the first embodiment, when the switching element 200 is turned on in the control mode, the gate voltage control unit 10 includes the initial threshold voltage Vth after being measured in the initial measurement mode 0 Since the gate voltage is controlled by the information of (a), even when the actual threshold voltage fluctuates from the designed threshold voltage due to manufacturing variations of the switching element 200, the gate voltage slightly exceeding the actual threshold voltage can be applied to the gate electrode according to the actual threshold voltage when the switching element 200 is put into the on state in the control mode. Therefore, compared with the case where a gate voltage far exceeding a threshold voltage designed in advance is applied to the gate electrode (comparative example, see fig. 8 (a)), the Turn-ON (Turn ON) period and the Turn-OFF (Turn OFF) period can be shortened, and thus the switching speed can be increased, and thus the switching loss of the switching element 200 can be reduced.
Generally, the actual threshold voltage of the switching element 200 is changed from the initial threshold voltage Vth due to the temperature variation of the switching element 200 0 Although it is difficult to accurately calculate the actual Δvgs because the variation and the resulting Δvgs are relatively small, according to the power module 1 according to the first embodiment, since the degradation determination unit 60 is based on the information on the temperature characteristics of the threshold voltage in the switching element 200, and based on the information including the initial Δvgs, the Δvgs detected in the degradation determination mode, and the initial operating temperature T 0 And the information of the operating temperature T of the switching element 200 detected by the temperature detecting unit 50 in the degradation determination mode, so that it is possible to calculate the threshold voltage in consideration of the temperature fluctuation and accurately calculate the actual Δvgs having a small value.
According to the power module 1 of the first embodiment, the threshold voltage calculation unit 70 includes the detection by the temperature detection unit 50The threshold voltage Vth of the switching element 200 at the time of operation is calculated from the information of the measured operation temperature T of the switching element 200, and when the switching element 200 is turned on in the control mode, the gate voltage control section 10 controls the gate voltage based on the threshold voltage Vth of the switching element 200 at the time of operation calculated by the threshold voltage calculating section 70, so that even when the operation temperature T of the switching element 200 at the time of operation is higher than the initial operation temperature T of the switching element 200 0 Thereby causing the threshold voltage Vth to be higher than the initial threshold voltage Vth 0 Even when the fluctuation occurs, a voltage slightly exceeding the threshold voltage Vth at the time of operation can be applied to the gate electrode. Therefore, the on period and the off period can be shortened, and thus, the switching loss can be reduced.
In addition, according to the power module 1 of the first embodiment, even when the difference between the absolute maximum rated voltage and the threshold voltage of the gate electrode such as the switching element formed of the material containing GaN is small, the voltage slightly exceeding the threshold voltage Vth at the time of operation can be applied to the gate electrode. Therefore, the on period and the off period can be shortened, and thus, the switching loss can be reduced. Further, it is possible to prevent "a phenomenon in which the switching element 200 cannot be brought into the on state even if a gate voltage slightly exceeding the threshold voltage (designed threshold voltage) is applied to the gate electrode" due to the temperature variation of the threshold voltage Vth, and thus the on/off operation of the switching element 200 can be accurately controlled.
According to the power module 1 of the first embodiment, in the degradation determination mode, the on/off state determination unit 30 determines the on/off state of the switching element 200 based on the detection result of the switching current Id detected by the switching current detection unit 20, and therefore, the threshold voltage of the switching element 200 can be easily and accurately measured.
Further, according to the power module 1 of the first embodiment, since the alarm unit 80 is provided to display the detection result of whether or not the device is degraded, which is determined by the degradation determination unit 60, on the outside, degradation can be known from the outside even when the device is actually used.
According to the power module 1 of the first embodiment, since the stress current supply unit 102 for supplying the stress current Is to the switching element 200 in the degradation determination mode Is provided, the power under the same condition can be supplied to the switching element 200 in the initial measurement mode and the degradation determination mode. Thus, the difference between the Δvgs and the initial Δvgs can be accurately calculated, and whether or not the deterioration is detected can be accurately determined.
In addition, according to the power module 1 of the first embodiment, since the gate voltage control unit 10 controls the gate voltage so that the gate voltage increases stepwise with the passage of time in the degradation determination mode and the initial measurement mode, the threshold voltage of the switching element 200 can be measured efficiently and accurately.
Next, according to the power module 1 of the first embodiment, since the switching element 200 is formed of a material including GaN, the on-resistance of the switching element 200 is reduced, and the on-loss of the power module can be reduced.
Embodiment two
The power module (not shown) according to the second embodiment basically has the same configuration as the power module 1 according to the first embodiment, but is different from the power module 1 according to the first embodiment in that the temperature characteristic calculating unit is provided. The power module according to the second embodiment implements a temperature characteristic measurement mode for measuring the temperature characteristic of the threshold voltage in the switching element 200 after implementing the control mode for a predetermined time.
The temperature characteristic calculation unit 90 is connected to the temperature detection unit 50 and the storage unit 40, and calculates the temperature characteristic of the threshold voltage in the switching element 200 (see fig. 11).
In the temperature characteristic measurement mode, the following operation is performed.
After the control mode is performed for a predetermined time, the measurement current Im is supplied from the measurement current supply unit 100 to the drain electrode of the switching element 200 in a state where no current is supplied from the driving power supply 420.
Subsequently, the gate voltage control section 10 controls the gate voltage so as to apply a voltage lower than the envisaged (in operation) threshold voltage to the gate electrode. At this time, since the switching current (the value of the switching current is 0) cannot be detected by the switching current detecting section 20, the on/off state determining section 30 determines that the switching element 200 is in the off state. If the on/off state determination unit 30 determines that the switching element 200 is in the off state, the gate voltage control unit 10 controls the gate voltage so as to raise the gate voltage by one stage (see fig. 4).
The gate voltage is stepped up (specifically, stepped up) after the above-described process is repeated, and when the switching current is detected by the switching current detecting section 20 (when the value of the switching current is not 0), the on/off state determining section 30 determines that the switching element 200 is in the on state. At this time, the operating temperature T of the switching element 200 detected by the temperature detecting unit 50 is set 2 To the storage section 40, and the storage section 40 stores it (refer to fig. 1). The gate voltage control unit 10 uses the gate voltage Vgs applied to the gate electrode as the threshold voltage Vth at the time of temperature characteristic measurement 4 To the memory unit 40, and the memory unit 40 uses the gate voltage Vgs as the threshold voltage Vth at the time of temperature characteristic measurement 4 To be stored.
Next, the temperature characteristic calculation unit 90 reads the data including the initial threshold voltage Vth from the storage unit 40 0 Measurement of initial threshold Voltage Vth 0 Initial operating temperature T of the switching element 200 0 Threshold voltage Vth at the time of temperature characteristic measurement 4 Reads the operating temperature T of the switching element 200 detected from the temperature detecting unit 50 in the temperature characteristic measuring mode, together with the information of (a) 2 And vth=vth respectively 4 T=t 2 Substituted into vth=vth 0 －α(T－T 0 ) The temperature characteristic (specifically, the temperature coefficient α) is calculated from the characteristic equation of (a). The calculated temperature coefficient α is stored in the storage unit 40.
In the control mode, the threshold voltage calculation unit 70 calculates the initial threshold voltage stored in the storage unit 40 based on the temperature coefficient α calculated in the temperature characteristic measurement mode, the operating temperature T of the switching element 200 detected by the temperature detection unit 50, and the temperature coefficient αVth 0 At the initial time of measurement of threshold voltage Vth 0 Initial operating temperature T of the switching element 200 0 The threshold voltage Vth during operation is calculated, and the gate voltage is controlled based on the threshold voltage Vth. In the degradation determination mode, the threshold voltage Vth after temperature correction is calculated using the temperature characteristic measured in the temperature characteristic measurement mode for the value after the threshold voltage is measured for the second time 2 ' and Vth 3 ’。
As described above, the power module according to the second embodiment is different from the power module 1 according to the first embodiment in that the power module further includes a temperature characteristic calculating unit, but is configured to implement a degradation determination mode in which Δvgs is calculated from information including a threshold voltage detected before a stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and whether or not the device is degraded is determined from the information including the Δvgs, so that it is possible to determine whether or not the device is degraded during actual use (during operation), and to prevent breakage of the device due to continued use in a degraded state.
Further, according to the power module of the second embodiment, since the power module includes the temperature characteristic calculating unit 90, the temperature characteristic calculating unit 90 calculates the initial threshold voltage Vth based on the initial threshold voltage Vth included therein 0 Measurement of initial threshold Voltage Vth 0 Initial operating temperature T of the switching element 200 0 The operating temperature T of the switching element 200 detected by the temperature detecting unit 50 in the temperature characteristic measuring mode 2 Threshold voltage Vth at the time of temperature characteristic measurement 4 Since the temperature characteristic of the threshold voltage in the switching element 200 is calculated, even when the temperature characteristic of the threshold voltage in the switching element 200 is deviated, the threshold voltage can be accurately calculated in consideration of the deviation of the temperature characteristic of the switching element 200 in the degradation determination mode, and thus Δvgs can be more accurately calculated.
According to the power module of the second embodiment, the power module has a temperatureA temperature characteristic calculation unit 90, the temperature characteristic calculation unit 90 including an initial threshold voltage Vth 0 Measurement of initial threshold Voltage Vth 0 Initial operating temperature T of the switching element 200 0 The operating temperature T of the switching element 200 detected by the temperature detecting unit 50 in the temperature characteristic measuring mode, and the threshold voltage Vth at the time of temperature characteristic measurement 4 Since the temperature characteristics of the threshold voltage in the switching element 200 are calculated, even when the actual temperature characteristics vary from the designed temperature characteristics due to the manufacturing variations of the switching element 200, the threshold voltage at the time of operation can be accurately calculated, and a voltage slightly exceeding the threshold voltage Vth at the time of operation can be accurately applied to the gate electrode. Therefore, the on period and the off period can be shortened, and thus, the switching loss can be reduced.
The power module according to the second embodiment has the same configuration as the power module 1 according to the first embodiment except that the power module further includes a temperature characteristic calculating unit, and therefore has the effects of the power module 1 according to the first embodiment.
Embodiment III
The power module 2 according to the third embodiment has basically the same structure as the power module 1 according to the first embodiment, but is different from the power module 1 according to the first embodiment in that the stress current supply unit is not provided. That Is, in the power module 2 according to the third embodiment, the power supplied from the power circuit 400 Is constant, and in the degradation determination mode, the stress current Is supplied from the driving power supply 420 (see fig. 12).
In the power circuit 400, since the resistance value of the load resistor 410 and the voltage value of the driving power source 420 are constant, the supplied electric power is also constant. In the degradation determination mode, after the threshold voltage Is measured for the first time, after the drive power supply 420 supplies power for a certain period (corresponding to the stress current Is), the drive power supply 420 Is turned off and the threshold voltage Is measured for the second time, whereby Δvgs Is calculated.
As described above, the power module 2 according to the third embodiment is different from the power module 1 according to the first embodiment in that the stress current supply unit is not provided, but is configured to implement the degradation determination mode in the same manner as the power module 1 according to the first embodiment, in which the Δvgs is calculated from the information including the threshold voltage detected before the stress current is supplied to the switching element and the threshold voltage detected after the stress current is supplied to the switching element, and the degradation of the device is determined from the information including the Δvgs, so that it is possible to determine whether the device is degraded or not at the time of actual use (at the time of operation), and it is possible to prevent the device from being damaged by continued use in the degraded state.
Further, according to the power module 2 of the third embodiment, since it does not include the stress current supply portion, the layout and the circuit configuration thereof are simpler than those of the case where the stress current supply portion is provided, and the device can be miniaturized.
The power module 2 according to the third embodiment has the same configuration as the power module 1 according to the first embodiment except that the stress current supply unit is not provided, and therefore has the effect of the power module 1 according to the first embodiment.
The present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments. The present invention can be implemented in various forms within a range not departing from the gist thereof, and for example, the following modifications can be made.
(1) The number of components and the like described in the above embodiments are merely examples, and can be changed within a range that does not impair the effects of the present invention.
(2) In each of the above embodiments, the measurement current Im is supplied from the measurement current supply unit 100 to the switching element 200 when the threshold voltage used in the control mode is measured, but the present invention is not limited thereto. For example, the threshold voltage used in the control mode may be measured by providing the threshold voltage measurement power supply 104 connected to the drain electrode of the switching element 200 and supplying a threshold voltage measurement current to the drain electrode of the switching element 200 (see fig. 13, power module 3 according to the first modification). With this configuration, since the threshold voltage can be measured under different conditions (such as the amount of current and the voltage) from the current supplied from the measurement current supply unit 100 used in the measurement of Δvgs, the threshold voltage used in the control mode can be accurately measured.
(3) In the above embodiments, the initial measurement mode, the control mode, and the degradation determination mode are implemented in the power module, but the present invention is not limited thereto. For example, the power module may be configured to perform only the control mode and the degradation determination mode. At this time, the initial threshold voltage Vth 0 And the initial Δvgs is stored in the storage section in advance.
(4) In the above embodiments, the threshold voltage at the time of operation is calculated in the control mode, and the gate voltage is controlled based on the threshold voltage at the time of operation, but the present invention is not limited thereto. For example, in the control mode, the gate voltage may be controlled based on the initial threshold voltage (see fig. 14, the power module 4 according to the second modification).
(5) In the above embodiments, information on the temperature characteristics of the threshold voltage in the switching element is regarded as satisfying vth=vth 0 －α(T－T 0 ) But the present invention is not limited thereto. For example, information related to the temperature characteristic of the threshold voltage in the switching element may be used as another characteristic expression, or may be used as data indicating the relationship (1 to 1) between the temperature and the threshold voltage stored in the storage unit in advance.
(6) In each of the above embodiments, in the initial measurement mode and the degradation determination mode, the gate voltage control unit 10 controls the gate voltage so that the gate voltage increases stepwise with the passage of time, but the present invention is not limited thereto. For example, the gate voltage control unit 10 may control the gate voltage so that the gate voltage is a pulse-shaped voltage having a pulse with a large amplitude with the passage of time (see fig. 15).
(7) In the above embodiments, the power module 1 includes one switching element, but the present invention is not limited thereto. The power module may include a plurality of switching elements. In this case, the power module may control the plurality of switching elements.
(8) In the above embodiments, the switching element is formed of a material including GaN, but the present invention is not limited thereto. The switching element may be made of SiC or Ga 2 O 3 And the like, or a material containing silicon.
(9) In the above embodiments, the MOSFET is used as the switching element, but the present invention is not limited thereto. Switching elements other than MOSFETs (for example, HEMTs, IGBTs, and the like) may be used as the switching elements.
(10) In the above embodiments, the control circuit and the power circuit of the power module may be formed on different semiconductor substrates, or may be formed on the same semiconductor substrate. The switching element and the circuit portion other than the switching element may be formed on a different semiconductor substrate, or the switching element (for example, a semiconductor element having a GaN horizontal structure) and the circuit portion other than the switching element may be formed on the same semiconductor substrate.
Symbol description
1. 2, 3, 4, 900 … power modules; 10. 910 … gate voltage control section; 20 … switch current detecting section; 30 … on/off state determining section; 40 … storage; a 50 … temperature detecting unit; 52 … temperature sensing element; 60 … degradation determining unit; 62 … Δvgs calculating section; 64 … standard determining section; a 70 … threshold voltage calculating unit; 80 … alarm part; 90 … temperature characteristic calculating section; a 100 … current supply unit for measurement; 102 … stress current provider; 200. 800 … switching element; 300 … gate drive power supply; 400 … power circuit; 410 … load resistance; 420 … drive power supply; a T1 … (+) side input terminal; t2 … (-) side input terminal; a T3 … (+) side output terminal; a T4 … (-) side output terminal; t5 … control terminal; v (V) DD … supply voltage; id … switch current; vth, vth 1 、Vth 2 、Vth 3 … threshold voltage; vth (Vth) 0 … initial threshold voltage; vth (Vth) 4 … threshold voltage at the time of measurement of temperature characteristics; t, T 1 、T 2 … operating temperature of the switching element; t (T) 0 … initial operating temperature; SW1, SW2, SW3 … switches.

Claims (13)

1. A power module, characterized by:
the power module is configured to be switched between a control mode for controlling on/off operations of a switching element having a first electrode, a second electrode, and a third electrode, and a degradation determination mode for calculating Δvgs based on information including a threshold voltage detected before a stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and determining whether or not a device is degraded based on information including the Δvgs,
the power module includes:
the switching element;
a third electrode voltage control section that controls a third electrode voltage so as to stepwise increase the third electrode voltage when a threshold voltage is measured in the degradation determination mode, and that controls the third electrode voltage so as to control on/off operation of the switching element in the control mode;
An on/off state determination unit that determines an on/off state of the switching element in the degradation determination mode;
a storage unit that stores an initial Δvgs of the switching element, and stores the third electrode voltage applied to the third electrode as a threshold voltage after the on/off state determination unit determines that the switching element is in an on state in the degradation determination mode;
a degradation determination unit that calculates the Δvgs from information including a threshold voltage detected before the stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element, and determines whether the device is degraded or not from information including the Δvgs and the initial Δvgs in the degradation determination mode; and
a power circuit connected in series with the switching element and having a load resistor and a driving power source,
wherein the Δvgs is a difference between a threshold voltage detected before the stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element,
The stress current is a current flowing through the switching element in order to apply a predetermined electric power to the switching element and thereby heat the switching element.
2. The power module of claim 1, wherein:
the power module is configured to implement an initial measurement mode that detects the initial Δvgs of the switching element prior to implementing the control mode, in which,
when the threshold voltage is measured, the third electrode voltage control unit controls the third electrode voltage so that the third electrode voltage is stepwise increased,
the on/off state determination section determines an on/off state of the switching element,
after the on/off state determination section determines that the switching element is in the on state, the storage section stores the third electrode voltage applied to the third electrode as a threshold voltage,
the degradation determination unit calculates the initial Δvgs based on information including an initial threshold voltage that is the threshold voltage detected before the stress current is supplied to the switching element and a threshold voltage detected after the stress current is supplied to the switching element.
3. The power module of claim 2, wherein:
in the control mode, the third electrode voltage control unit controls the third electrode voltage based on information including the initial threshold voltage measured in the initial measurement mode when the switching element is turned on.
4. A power module according to any one of claims 1 to 3, further comprising:
a temperature detection unit for detecting an operation temperature of the switching element,
wherein the storage section further stores information on a temperature characteristic of a threshold voltage in the switching element and information including an initial operation temperature of the switching element, and the degradation determination section determines whether the device is degraded based on the information on the temperature characteristic of the threshold voltage in the switching element and based on the information including the initial Δvgs, the Δvgs detected in the degradation determination mode, the initial operation temperature, and the operation temperature of the switching element detected by the temperature detection section in the degradation determination mode.
5. The power module of claim 4, further comprising:
A threshold voltage calculating unit that calculates a threshold voltage at the time of operation of the switching element based on information including the operation temperature of the switching element, the initial threshold voltage, and the initial operation temperature of the switching element detected by the temperature detecting unit, and based on information related to a temperature characteristic of a threshold voltage in the switching element,
in the control mode, when the switching element is turned on, the third electrode voltage control unit controls the third electrode voltage based on the threshold voltage at the time of operation calculated by the threshold voltage calculation unit.
6. The power module of claim 4, wherein:
further implementing a temperature characteristic measurement mode for measuring a temperature characteristic of a threshold voltage in the switching element,
the power module further includes a temperature characteristic calculation unit that calculates a temperature characteristic of a threshold voltage in the switching element,
in the temperature characteristic measurement mode of the present invention,
the third electrode voltage control section controls the third electrode voltage so as to stepwise increase the third electrode voltage,
The on/off state determination section determines whether the switching element has been turned on,
after the on/off state determination section determines that the switching element is in the on state, the storage section stores the operating temperature of the switching element and stores the third electrode voltage applied to the third electrode as a threshold voltage at the time of temperature characteristic measurement of the switching element,
the temperature characteristic calculation unit calculates a temperature characteristic of a threshold voltage in the switching element based on information including the initial threshold voltage, the initial operation temperature of the switching element after the initial threshold voltage is measured, the operation temperature of the switching element detected by the temperature detection unit in the temperature characteristic measurement mode, and a threshold voltage at the time of measurement of the temperature characteristic.
7. A power module according to any one of claims 1 to 3, further comprising:
a first electrode current detection unit that detects a first electrode current flowing through the switching element,
in the degradation determination mode, the on/off state determination section determines the on/off state of the switching element based on a detection result of the first electrode current detected by the first electrode current detection section.
8. A power module according to any one of claims 1 to 3, further comprising:
and an alarm unit that externally displays a detection result of whether or not the device determined by the degradation determination unit is degraded.
9. A power module according to any one of claims 1 to 3, further comprising:
and a stress current supply unit that supplies the stress current to the switching element in the degradation determination mode.
10. A power module according to any one of claims 1 to 3, characterized in that: wherein the power provided in the power circuit is constant,
in the degradation determination mode, the stress current is supplied from a current flowing in the driving power supply.
11. A power module according to any one of claims 1 to 3, characterized in that:
wherein the third electrode voltage control section controls the third electrode voltage so that the third electrode voltage increases stepwise with the passage of time in the case of detecting the threshold voltage of the switching element.
12. A power module according to any one of claims 1 to 3, characterized in that:
When detecting the threshold voltage of the switching element, the third electrode voltage control unit controls the third electrode voltage so that the third electrode voltage becomes a pulse-shaped voltage having a pulse with a large amplitude with the passage of time.
13. A power module according to any one of claims 1 to 3, characterized in that:
wherein the switching element is made of GaN, siC or Ga 2 O 3 Is formed of the material of (a).
CN201780097627.5A 2017-12-22 2017-12-22 Power module Active CN111448747B (en)

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PCT/JP2017/046185 WO2019123643A1 (en) 2017-12-22 2017-12-22 Power module

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